Geometrically exact dynamic models for soft robotic manipulators

Unlike traditional rigid-linked robots, soft robotic manipulators can bend into a wide variety of complex shapes due to control inputs and gravitational loading. This paper presents a new approach for modeling the dynamics of soft robotic manipulators that incorporates the effect of material nonlinearities and distributed and payload weight and is geometrically exact for the large curvature, shear, torsion and extension that often occur in these manipulators. The model is based on the general Cosserat theory of rods and a fiber reinforced model of air muscle actuators. The model is validated experimentally on the OctArm V manipulator, showing less that 5% average error for a wide range of actuation pressures and base orientations as compared to almost 50% average error for the constant curvature model previously used by researchers.